comprehensive-rust/src/concurrency/shared_state.md

# Shared State

Rust uses the type system to enforce synchronization of shared data. This is
primarily done via two types:

- [`Arc<T>`][1], atomic reference counted `T`: handles sharing between threads
  and takes care to deallocate `T` when the last reference is dropped,
- [`Mutex<T>`][2]: ensures mutually exclusive access to the `T` value.

[1]: https://doc.rust-lang.org/std/sync/struct.Arc.html
[2]: https://doc.rust-lang.org/std/sync/struct.Mutex.html
Publish Comprehensive Rust 🦀 2022-12-21 16:36:30 +01:00			`# Shared State`

			`Rust uses the type system to enforce synchronization of shared data. This is`
			`primarily done via two types:`

Format all Markdown files with `dprint` (#1157) This is the result of running `dprint fmt` after removing `src/` from the list of excluded directories. This also reformats the Rust code: we might want to tweak this a bit in the future since some of the changes removes the hand-formatting. Of course, this formatting can be seen as a mis-feature, so maybe this is good overall. Thanks to mdbook-i18n-helpers 0.2, the POT file is nearly unchanged after this, meaning that all existing translations remain valid! A few messages were changed because of stray whitespace characters: msgid "" "Slices always borrow from another object. In this example, `a` has to remain " -"'alive' (in scope) for at least as long as our slice. " +"'alive' (in scope) for at least as long as our slice." msgstr "" The formatting is enforced in CI and we will have to see how annoying this is in practice for the many contributors. If it becomes annoying, we should look into fixing dprint/check#11 so that `dprint` can annotate the lines that need fixing directly, then I think we can consider more strict formatting checks. I added more customization to `rustfmt.toml`. This is to better emulate the dense style used in the course: - `max_width = 85` allows lines to take up the full width available in our code blocks (when taking margins and the line numbers into account). - `wrap_comments = true` ensures that we don't show very long comments in the code examples. I edited some comments to shorten them and avoid unnecessary line breaks — please trim other unnecessarily long comments when you see them! Remember we're writing code for slides :smile: - `use_small_heuristics = "Max"` allows for things like struct literals and if-statements to take up the full line width configured above. The formatting settings apply to all our Rust code right now — I think we could improve this with https://github.com/dprint/dprint/issues/711 which lets us add per-directory `dprint` configuration files. However, the `inherit: true` setting is not yet implemented (as far as I can tell), so a nested configuration file will have to copy most or all of the top-level file. 2023-12-31 00:15:07 +01:00			- [`Arc<T>`][1], atomic reference counted `T`: handles sharing between threads
			and takes care to deallocate `T` when the last reference is dropped,
			- [`Mutex<T>`][2]: ensures mutually exclusive access to the `T` value.
Publish Comprehensive Rust 🦀 2022-12-21 16:36:30 +01:00
			`[1]: https://doc.rust-lang.org/std/sync/struct.Arc.html`
			`[2]: https://doc.rust-lang.org/std/sync/struct.Mutex.html`